The present invention is directed to a fiber optic or wave guide faceplate for transmission of a light signal from or to a source or detector. More particularly, the present invention provides a faceplate for use with an array of sources or detectors in which the optical fibers or wave guides are precisely aligned with the sources or detectors.
Fiber optic faceplates are known in the field of imaging applications. In these prior known faceplates, it was desirable that the fibers be as small as possible to improve resolution of the sample image. In the past, faceplates have been fabricated with fiber sizes as small as three microns. Typically, these faceplates utilized an over-sampled approach in which as large a number as possible of these small fibers were utilized within the area of an optical source or detector in order to transmit a light signal. An example of a faceplate having an over-sampled approach is shown in FIG. 1, where the optical fibers 7 are closely packed. The interface with the pixels 8 of the optic sources or detectors is a random alignment. The actual active optical fibers are designated as 7xe2x80x2 and shown with an unshaded center.
This over-sampled approach allows for ease of alignment of the array to the source or detector. However, this approach has inherent drawbacks as additional source and detector pixels are added. It has been recently proposed to move to two-dimensional arrays of sources and detectors having over four hundred elements. In such applications, there is an increase in the desire to save power and thus reduce the amount of heat generated. With the over-sampled approach, over 30% percent of the light is lost to the cladding surrounding each fiber. In addition, it is desirable to provide faceplates having optical fibers which are compatible with the system optical fibers. This indicates a future need for faceplates having graded index (GRIN) fibers and single mode fibers. These structures are not possible with the known over-sampled approaches.
It would be desirable to provide a faceplate having precision-aligned fibers located in the position of the pixel areas of the sources or detectors which are being optically linked.
Briefly stated, the present invention is directed to a fiber optic faceplate for coupling with optical sources or detectors. The optical sources or detectors are arranged in a two-dimensional array. Each of the sources or detectors has a pixel area precisely located at a predetermined x-y coordinate spaced at an equal distance from neighboring pixel areas. The faceplate includes a plurality of drawn and fused optic fibers and interstitial fillers. Each of the optic fibers is positioned at a corresponding position to the pixel areas of the optical sources or detectors. The optic fibers are drawn to an outside diameter corresponding to the spacing distance between the predetermined x-y coordinates. The interstitial fillers are located at each interstitial space between optic fibers and have an outside diameter corresponding to the space between the optic fibers to maintain the optic fibers in an aligned position as they are drawn.
In another aspect, the present invention provides a fiber optic faceplate for coupling with optical sources or detectors. The optical sources or detectors are arranged in a two-dimensional array, with each individual source or detector being precisely located at predetermined position spaced apart from neighboring sources or detectors. The faceplate includes a plurality of drawn and fused optic fiber bundles. Each optic fiber bundle includes a plurality of optic fibers and has a greater cross-sectional area than an area of a pixel of the source or detector. Each optic fiber bundle is located in a generally aligned position with a corresponding pixel of the source or detector such that the pixel is aligned with at least half of the active area of the corresponding bundle. A filling material is located between the adjacent fiber bundles to maintain the fiber bundle in position as they are drawn and fused.
In another aspect, the present invention provides a wave guide faceplate including a plurality of fused and drawn wave guides and interstitial fillers. Each of the wave guides is positioned at a corresponding position to the optical sources or detectors. The wave guides have an outside diameter corresponding to the spacing distance between predetermined x-y coordinates. The interstitial fillers are located at each interstitial space between neighboring wave guides and have an outside diameter corresponding to the space between the wave guides to maintain the wave guides in an aligned position as they are drawn.